A Bronx mother is desperate for answers after her daughter mysteriously died while in NYPD custody over the July 4 holiday weekend.

Authorities are investigating the death of an 18-year-old woman who was taken unconscious to a hospital over the weekend from an NYPD stationhouse in the Bronx where she was being held, according to police.

A 77-year-old woman was beaten to death in a Bronx home Monday, police said. Authorities found the unconscious woman with head injuries in the house near Barnes and Brady avenues in Pelham Parkway at around 7:30 a.